javaspringboot创建微信支付，使用apiv2 JSAPI支付代码怎么写

下面是一个简单的Java Spring Boot微信支付示例，使用APIv2 JSAPI支付代码：

1. 创建微信支付配置类

@Configuration
public class WechatPayConfig {

    @Value("${wechat.pay.appId}")
    private String appId;

    @Value("${wechat.pay.mchId}")
    private String mchId;

    @Value("${wechat.pay.apiKey}")
    private String apiKey;

    @Bean
    public WXPay wxPay() throws Exception {
        WXPayConfigImpl config = WXPayConfigImpl.getInstance();
        config.setAppID(appId);
        config.setMchID(mchId);
        config.setKey(apiKey.getBytes());
        return new WXPay(config);
    }

}

2. 创建微信支付控制器

@RestController
@RequestMapping("/api/wechat/pay")
public class WechatPayController {

    @Autowired
    private WXPay wxPay;

    @PostMapping("/unifiedorder")
    public ResponseEntity<?> unifiedOrder(@RequestBody WechatPayRequest request, HttpServletRequest httpRequest) {
        try {
            // 构造支付请求参数
            Map<String, String> data = new HashMap<>();
            data.put("body", request.getBody());
            data.put("out_trade_no", request.getOutTradeNo());
            data.put("total_fee", request.getTotalFee().toString());
            data.put("spbill_create_ip", httpRequest.getRemoteAddr());
            data.put("notify_url", "https://your-notify-url.com");
            data.put("trade_type", "JSAPI");
            data.put("openid", request.getOpenid());

            // 调用统一下单API
            Map<String, String> result = wxPay.unifiedOrder(data);

            // 生成JSAPI支付参数
            String prepayId = result.get("prepay_id");
            Map<String, String> jsApiParams = new HashMap<>();
            jsApiParams.put("appId", wxPay.getConfig().getAppID());
            jsApiParams.put("timeStamp", String.valueOf(System.currentTimeMillis() / 1000));
            jsApiParams.put("nonceStr", WXPayUtil.generateNonceStr());
            jsApiParams.put("package", "prepay_id=" + prepayId);
            jsApiParams.put("signType", "MD5");
            String paySign = WXPayUtil.generateSignature(jsApiParams, wxPay.getConfig().getKey());
            jsApiParams.put("paySign", paySign);

            return ResponseEntity.ok(jsApiParams);
        } catch (Exception e) {
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(e.getMessage());
        }
    }

}

3. 创建微信支付请求类

public class WechatPayRequest {

    private String body;
    private String outTradeNo;
    private BigDecimal totalFee;
    private String openid;

    // getters and setters

}

4. 在application.properties文件中添加微信支付配置

wechat.pay.appId=your-appId
wechat.pay.mchId=your-mchId
wechat.pay.apiKey=your-apiKey

5. 使用Postman等工具测试JSAPI支付接口

发送POST请求到http://localhost:8080/api/wechat/pay/unifiedorder，请求体如下：

{
    "body": "测试支付",
    "outTradeNo": "20220101000001",
    "totalFee": 1,
    "openid": "your-openid"
}

其中，openid是JSAPI支付必须的参数，可以通过微信OAuth2.0授权获取。

返回结果如下：

{
    "appId": "your-appId",
    "timeStamp": "1641260647",
    "nonceStr": "9jvOvEJZzVw2STN5",
    "package": "prepay_id=wx01155047389241f9c9ab15d8d8e9813000",
    "signType": "MD5",
    "paySign": "B24F9D7F2DBE3048F7BA4D400C4B0B4B"
}

将返回结果中的数据传递给微信JSAPI支付接口即可完成支付。